Campfire Audio Holocene: how much amplifier do you need?

The Campfire Audio Holocene is 9Ω. Campfire Audio publishes no sensitivity figure for it at all, so every requirement on this page rests on a 94.0 dB figure collected when this database was first built and never traced to a manufacturer document. Read as per milliwatt it needs 4.0 mW to reach 100 dB SPL, or 0.19 V across the drivers — an estimate, not a specification.

That puts it in the easy category. A phone, a laptop headphone jack or the cheapest USB dongle will drive it to painful levels. Of the 280 sources in the database, 188 have at least 10 dB of headroom and another 81 have enough. The cheapest portable source that does the job is the Apple USB-C dongle (US) at $9.

Campfire Audio does not publish a sensitivity figure for this model at all. The number above was collected when this database was first built and has never been traced to a manufacturer document, so every figure on this page that depends on it is an estimate rather than a specification. The provenance section below says where it came from.

Campfire Audio does not publish a sensitivity figure for this model at all. The number above was collected while this database was first built and has not been traced to a manufacturer document.

Source: campfireaudio.com. How this data was built.

Most people listen between 75 and 85 dB. The 100 dB row is the one worth planning around: it gives you headroom for dynamic peaks without designing your system for a volume that would damage your hearing in under fifteen minutes. The safe listening calculator puts numbers on that.

Every source in the database, judged at 100 dB SPL into 9Ω. “Headroom” is how much power is left over above what the headphone needs — 10 dB means ten times the required power, which is what you want for dynamic peaks.

Hiss. At 114.5 dB/V these are sensitive enough to reveal a source's own noise floor. The noisiest source in the database, the Schiit Mjolnir 3, would put its hiss at roughly 22 dB SPL in these headphones — clearly audible in quiet passages. The hiss calculator lets you check your own amplifier's noise figure.

Output impedance. At 9Ω these want a source output impedance below 1.12Ω to satisfy the one-eighth rule. Of the 192 sources that publish one, 49 miss it, the worst being the Bottlehead Crack (OTL kit) at 120.0Ω; the other 88 publish no output impedance at all, so they cannot be checked either way. Above that threshold the source starts shaping the frequency response. Check yours here.

Worked out in advance against its own stable: vs Andromeda 10 · vs Andromeda 2023 · vs Astrolith · vs Chimera. Each of those pages counts the sources that drive one and not the other.

Or open the comparison tool to put any two models side by side, or browse all 578. Or see every Campfire Audio headphone in the database, and how much of what this site says about them came from Campfire Audio’s own documents.